Fuel Everywhere

[Matt]

Im trying to get Emilia back on the road and im getting a lot of hiccups along the way.

I have a few electrical gremlins to sort out before the MoT, but im having major problems with fuel/carb. I have a HIF44 and its leaking petrol like nobodys business. The fuel appears to be coming up through the jet. I have replaced the float chamber valve and it made no difference, I have also tried 2 other carbs and they both do the same

Has anyone got any suggestions?

[AndrewSkinner]

Hey! sorry to hear about your problems. if it does it with other carbs then A) you are very unlucky to have the same problem with three carbs (Unlikely) or B) it is not the carb and is something else. The next problem would be the pump. Have you tried checking the fuel pump points? The pump may not be cutting off when the pressure in the fuel line rises?

Another problem could be the actual float sinking (Filling with fuel) OR what happened to mine was that the float was bent as was catching on the wall of the chamber! but this is unlikely if you have tried several other carbs?

good luck!!

[alex_holden]

Have you tried checking the fuel pump points? The pump may not be cutting off when the pressure in the fuel line rises?

I agree it sounds like it could be excessive fuel pressure, however it can't be the points because the pump doesn't work like that. The solenoid sucks the fuel from the tank while compressing the spring, then the spring supplies the force to eject the fuel.

[AndrewSkinner]

ah right! Could it be something like the spring is too forceful??

It most likely to be to do with the pump if other carbs do exactly the same?

[Matt]

I tried a few more HIF carbs and they all do the same... first HS I put on and it doesnt leak... shame the biggest I have is an HS4

[MoggyTech]

I tried a few more HIF carbs and they all do the same... first HS I put on and it doesnt leak... shame the biggest I have is an HS4

Definately excessive fuel pressure then. This would suggest the HIF carb has a smaller float chamber? or smaller float. The result of this would be the float needle valve would be forced off it's seat resulting in float chamber flooding. An inline fuel restrictor between pump and carb would fix that.

[bmcecosse]

Sure you aren't putting the fuel in the overflow pipe - rather than the correct inlet pipe ? The floats/valves on these carbs are usually very good - and can tolerate wide range of mounting angles.

[Matt]

Thanks BMC... But it was connected correctly. In fact it was still connected from immedately after the rebuild when it was fine. Leave it a few months and suddenly fuel starts peeing out!

The HS has the smaller float in dia... i would anticipate they both displace a similar amount